Thermodynamics second-law analysis of hydrocarbon diffusion flames: Effects of soot and temperature

Zhang, Zhongnong; Lou, Chun; Long, Yan; Kumfer, Benjamin M.

doi:10.1016/j.combustflame.2021.111618

Cited by 11 publications

(6 citation statements)

References 34 publications

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“…The conservation equations for mass, momentum, energy, and species mass fraction as well as two transport equations of soot particles in a two-dimensional axisymmetric cylindrical coordinate are solved in this code. As with the models in [ 18 ], the DLR mechanism [ 21 ], the abstraction of H, the C (HACA) soot model [ 22 ], the discrete-ordinates method (DOM), and the statistical narrow-band correlated-k model (SNBCK) [ 23 ] were included in the Coflame code.…”

Section: Methodsmentioning

confidence: 99%

“…According to previous work [ 3 , 8 , 9 , 18 ], entropy generation in a flame is mainly due to four irreversible processes: thermal radiation, heat conduction and convection, mass diffusion, and chemical reactions. The total local volumetric entropy generation rate can be computed as follows:

where

, and

are the local volumetric entropy generation rates due to thermal radiation, heat conduction and convection, mass diffusion, and chemical reactions, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, the effects of non-gray characteristics of three-atom gases (CO 2 and H 2 O), soot particles, and boundary walls on radiation entropy generation were evaluated [ 14 , 15 , 16 ]. Consequently, the relationships between flame temperature, soot formation, local entropy generation, and thermodynamic irreversibility in flames have been quantitatively analyzed [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamics Irreversibilities Analysis of Oxy-Fuel Diffusion Flames: The Effect of Oxygen Concentration

Yan

Tang

Wang

et al. 2022

Entropy

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In studies on the combustion process, thermodynamic analysis can be used to evaluate the irreversibility of the combustion process and improve energy utilization efficiency. In this paper, the combustion process of a laminar oxy-fuel diffusion flame was simulated, and the entropy generation due to the irreversibilities of the radiation process, the heat conduction and heat convection process, the mass diffusion process, and the chemical reaction process was calculated. The effect of the oxygen concentration in the oxidizer on the entropy generation was analyzed. The results indicated that, as the oxygen concentration in the oxidizer increases, the radiative entropy generation first increases and then decreases, and the convective and conductive entropy generation, the mass diffusion entropy generation, the chemical entropy generation, and the total entropy generation gradually increase.

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Section: Methodsmentioning

confidence: 99%

where

, and

are the local volumetric entropy generation rates due to thermal radiation, heat conduction and convection, mass diffusion, and chemical reactions, respectively.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermodynamics Irreversibilities Analysis of Oxy-Fuel Diffusion Flames: The Effect of Oxygen Concentration

Yan

Tang

Wang

et al. 2022

Entropy

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“…It is obvious that this analytical method is better suited to the practical industrial furnace situation. Therefore, this approach was applied to various problems of thermodynamic analysis of high-temperature systems including 1-D high-temperature systems with participating medium including CO 2 , H 2 O, even soot [ 14 , 15 ], lab-scale hydrocarbon diffusion flames [ 16 , 17 , 18 ], as well as practical combustion facilities [ 19 , 20 , 21 ]. During the above studies, it was found that the thermodynamic role of thermal radiation in the combusting flows should be paid more attention, and the variation in temperature and radiative properties in combustion chambers would have crucial effects on REG.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Irreversibility Analysis of Thermal Radiation in Coal-Fired Furnace: Effect of Coal Ash Deposits

Zhang

Lou

2023

Materials

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In this paper, a three-dimensional (3-D) high-temperature furnace filled with a gas-solid medium was investigated, and the radiative transfer equation and the radiative entropy transfer equation in the chamber were applied in order to analyze the effect of coal deposits on thermal radiation. The heat flux on the walls of the furnace and the entropy generation rate were determined due to the irreversibility of the radiative heat transfer process in the furnace. Furthermore, the effect of ash deposits on the wall surface on the irreversibility of the radiation heat transfer process was investigated. The numerical results show that when burning bituminous and sub-bituminous coal, ash deposits in the furnace led to a 48.2% and 63.2% decrease in wall radiative heat flux and a 9.1% and 12.4% decrease in the radiative entropy rate, respectively. The ash deposits also led to an increase in the entropy generation number and a decrease in the thermodynamic efficiency of the radiative heat transfer process in the furnace.

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“…Datta [ 17 , 18 ] calculated the entropy generation in a laminar jet diffusion flame, and he analyzed the effect of gravity on the rate of entropy generation. Meanwhile, Lou et al [ 19 , 20 , 21 , 22 , 23 ] calculated the radiative entropy generation in flames, and they also investigated the effects of soot and temperature on entropy generation in hydrocarbon flames. Recently, the thermodynamics second-law analysis of the combustion process of hydrogen has received extensive attention.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Exergy Loss of Ammonia Addition in Hydrocarbon Diffusion Flames

Sun

Zhang

Sun

et al. 2022

Entropy

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In this paper, a theoretical numerical analysis of the thermodynamics second law in ammonia/ethylene counter-flow diffusion flames is carried out. The combustion process, which includes heat and mass transfer, as well as a chemical reaction, is simulated based on a detailed chemical reaction model. Entropy generation and exergy loss due to various reasons in ammonia/ethylene and argon/ethylene flames are calculated. The effects of ammonia addition on the thermodynamics efficiency of combustion are investigated. Based on thermodynamics analysis, a parameter, the lowest emission of pollutant (LEP), is proposed to establish a relationship between the available work and pollutant emissions produced during the combustion process. Chemical reaction paths are also analyzed by combining the chemical entropy generation, and some important chemical reactions and substances are identified. The numerical results reveal that ammonia addition has a significant enhancement on heat transfer and chemical reaction in the flames, and the total exergy loss rate increases slightly at first and then decreases with an increase in ammonia concentration. Considering the factors of thermodynamic efficiency, the emissions of CO2 and NOx reach a maximum when ammonia concentration is near 10% and 30%, respectively. In terms of the chemical reaction path analysis, ammonia pyrolysis and nitrogen production increase significantly, while ethylene pyrolysis and carbon monoxide production decrease when ammonia is added to hydrocarbon diffusion flames.

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Thermodynamics second-law analysis of hydrocarbon diffusion flames: Effects of soot and temperature

Cited by 11 publications

References 34 publications

Thermodynamics Irreversibilities Analysis of Oxy-Fuel Diffusion Flames: The Effect of Oxygen Concentration

Thermodynamics Irreversibilities Analysis of Oxy-Fuel Diffusion Flames: The Effect of Oxygen Concentration

Thermodynamic Irreversibility Analysis of Thermal Radiation in Coal-Fired Furnace: Effect of Coal Ash Deposits

Numerical Investigation of Exergy Loss of Ammonia Addition in Hydrocarbon Diffusion Flames

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